Physics
posted by Shawna on .
Zero, a hypothetical planet, has a mass of 2.7 x 10^23 kg, a radius of 2.8 x 10^6 m, and no atmosphere. A 3.6 kg space probe is to be launched vertically from its surface. (a) If the probe is launched with an initial kinetic energy of 8.0 × 10^7 J, what will be its kinetic energy when it is 3.7 × 10^6 m from the center of Zero? (b) If the probe is to achieve a maximum distance of 4.6 × 10^6 m from the center of Zero, with what initial kinetic energy must it be launched from the surface of Zero?

Intial total energy= final total energy
Initial KE+INitial PE=KE2+PE2
where ke2= 1/2 mv^r at some r, and pe2=GMm/r